How to validate an email address in JavaScript

You should not use regular expressions to validate an input string to check if it's an email. It's too complicated and would not cover all the cases.

Now since you can only cover 90% of the cases, write something like:

function isPossiblyValidEmail(txt) {

   return txt.length > 5 && txt.indexOf('@')>0;

}

You can refine it. For instance, 'aaa@' is valid. But overall you get the gist. And don't get carried away... A simple 90% solution is better than 100% solution that does not work.

The world needs simpler code...

4 years ago

Here is a regular expression to validate email.

function validateEmail(email) {

    const re = /^(([^<>()[\]\\.,;:\s@"]+(\.[^<>()[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;

    return re.test(String(email).toLowerCase());

}

4 years ago

function ValidateEmail(inputText)
{
var mailformat = /^[a-zA-Z0-9.!#$%&'+/=?^_`{|}~-]+@[a-zA-Z0-9-]+(?:\.[a-zA-Z0-9-]+)$/;
if(inputText.value.match(mailformat))
{
alert("Valid email address!");
document.form1.text1.focus();
return true;
}
else
{
alert("You have entered an invalid email address!");
document.form1.text1.focus();
return false;
}
}

4 years ago